[Bug tree-optimization/84178] New: [7/8 Regression] ICE in release_bb_predicate

["asolokha at gmx dot com" <gcc-bugzilla at gcc dot gnu dot org>]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=84178

            Bug ID: 84178
           Summary: [7/8 Regression] ICE in release_bb_predicate
           Product: gcc
           Version: 7.3.0
            Status: UNCONFIRMED
          Keywords: ice-on-valid-code
          Severity: normal
          Priority: P3
         Component: tree-optimization
          Assignee: unassigned at gcc dot gnu.org
          Reporter: asolokha at gmx dot com
  Target Milestone: ---

gcc-8.0.0-alpha20180128 snapshot (r257131) and gcc 7.3.0 ICE when compiling the
following snippet w/ -O3 -fno-tree-forwprop:

int zy, h4;

void
r8 (long int mu, int *jr, int *fi, short int dv)
{
  do
    {
      int tx;

      tx = !!h4 ? (zy / h4) : 1;
      mu = tx;
      *jr = (((unsigned char) mu > (254 >> dv)) ? 0 : (unsigned char) tx) +
*fi;
    } while (*jr == 0);

  r8 (mu, jr, fi, 1);
}

% gcc-8.0.0-alpha20180128 -O3 -fno-tree-forwprop -c rhoqpgf1.c
during GIMPLE pass: ifcvt
rhoqpgf1.c: In function 'r8.constprop':
rhoqpgf1.c:4:1: internal compiler error: in release_bb_predicate, at
tree-if-conv.c:286
 r8 (long int mu, int *jr, int *fi, short int dv)
 ^~
0x664d68 release_bb_predicate
       
/var/tmp/portage/sys-devel/gcc-8.0.0_alpha20180128/work/gcc-8-20180128/gcc/tree-if-conv.c:286
0x664d68 free_bb_predicate
       
/var/tmp/portage/sys-devel/gcc-8.0.0_alpha20180128/work/gcc-8-20180128/gcc/tree-if-conv.c:300
0x664d68 tree_if_conversion(loop*)
       
/var/tmp/portage/sys-devel/gcc-8.0.0_alpha20180128/work/gcc-8-20180128/gcc/tree-if-conv.c:2897
0xd092e5 execute
       
/var/tmp/portage/sys-devel/gcc-8.0.0_alpha20180128/work/gcc-8-20180128/gcc/tree-if-conv.c:2962

gcc 7 ICEs w/ different backtrace, though.